在字节模式和异步中重用NamedPipeServerStream的正确方法

时间:2011-03-31 05:41:39

标签: .net asynchronous named-pipes

我正在设置一个命名管道服务器并且我从服务器管道中读取...我允许5个可能的并发连接,并且它们是这样设置的。

Public Sub Start()
    Dim i As Integer
    While i < mTotalServers
        Dim s As New IO.Pipes.NamedPipeServerStream("IPSClient", IO.Pipes.PipeDirection.InOut,
                 mTotalServers, IO.Pipes.PipeTransmissionMode.Byte, IO.Pipes.PipeOptions.Asynchronous)
        i += 1
        Dim p As New PipeConnection(s, "Index - " & i)
        mServers.Add(p)

        s.BeginWaitForConnection(New AsyncCallback(AddressOf ConnectionReceived), p)
    End While
End Sub

然后我恢复操作直到收到连接。

Private Sub ConnectionReceived(ar As IAsyncResult)
    Try
        Dim p As PipeConnection = Nothing
        If ar.IsCompleted Then
            Diagnostics.Debug.Print("Connection received")
            p = CType(ar.AsyncState, PipeConnection)
            Dim s As IO.Pipes.NamedPipeServerStream = p.Stream
            s.EndWaitForConnection(ar)

            Dim conn As Connection = New Connection(p)

            While mRunning AndAlso p.Stream.IsConnected
                If p.ReadHandle.WaitOne(100) Then
                    Debug.Print("Set")
                Else
                    '
                End If
            End While

            If mRunning Then
                s.BeginWaitForConnection(New AsyncCallback(AddressOf ConnectionReceived), p)
            End If
        Else
            p.Stream.Close()
            p.Stream.Dispose()
        End If

    Catch ex As ObjectDisposedException
        ' Diagnostics.Debug.Print(ex.ToString)
    Catch ex As OperationCanceledException
        Diagnostics.Debug.Print(ex.ToString)
    Catch ex As IO.IOException
        Diagnostics.Debug.Print(ex.ToString)
    End Try
End Sub

一旦管道的客户端断开连接,我希望管道可以重复使用。

我正在循环的部分虽然mRunning和连接,这是我应该怎么做,还是有更好的方法? (我的阅读代码全部发生在连接类中)

同样在我再次使用BeginWaitForConnection的块的底部,这是正确的吗?

1 个答案:

答案 0 :(得分:1)

at the bottom of the block where I BeginWaitForConnection again, is that correct

不,不是。连接后,NamedPipeServerStream的实例只是围绕将服务器连接到特定客户端的管道实例的Stream。它不是为了重复使用而设计的。您的代码应该只将此实例交给您的Connection对象,这应该确保在与该客户端的通信完成时将其处理掉。

要重用mServers中的“插槽”,当客户端连接完成时释放该插槽,您需要在某处实例化新的NamedPipeServerStream并在其上调用BeginWaitForConnection。看起来您的PipeConnection类可能是实现它的地方。